The present invention relates generally to the field of data storage systems, and more particularly to multi-site heat map management.
As data storage demands have increased, various distributed data storage models have emerged, including networked data storage environments where data is stored on an interconnected network of storage systems. Such an environment may include storage systems located at different data sites. A data site may serve as a backup for a main data site to protect against failure of the main data site, in which case only one of the data sites serves data to client devices at a time. Panache is a protocol for a multi-site server configuration wherein a main data site (also called a home data site) stores primary file data and a cache data site maintains cached file data by replicating and storing the primary file data. Both the home data site and the cache data site may simultaneously serve data to clients. In such a case, each client application can access the stored data from the home site or the cache site and may access the site with the lowest latency or the site which is geographically closest.
Multi-tiered storage is a storage method in which data is stored on various types of storage media based on workload activity metrics stored as heat values in a heat map. A workload activity metric may be calculated for contiguous areas of storage in a computer file system in a logical volume, such as extents. The heat value may be a number on a scale and may be expressed as a temperature gradient from hot (high activity) to cold (low activity). Storing hot data on a fast storage tier and colder data on a slow storage tier improves overall performance of the storage system. The fast storage tier may comprise storage media with lower file access times than the slow storage tier. For example, the fast storage tier may comprise a plurality of solid-state drives while the slow storage tier comprises a plurality of hard disk drives. The heat map associates extents with heat values. As metrics are tracked over time, the heat map is adjusted and the data may be relocated among the storage tiers appropriately. Multi-tier data sites serving data to clients may each have a heat map based upon the workload activity of each respective data site.